Multiple label-free biodetection and quantitative DNA-binding assays on a nanomechanical cantilever array

Area of Science:

• Nanotechnology
• Biophysics
• Molecular Biology

Background:

• Label-free detection of biomolecules is crucial for diagnostics and research.
• Existing methods often require sample labeling or are time-consuming.
• Microcantilevers offer a sensitive platform for detecting molecular binding events.

Purpose of the Study:

• To develop a microarray of cantilevers for simultaneous, label-free detection of multiple unlabeled biomolecules.
• To investigate the nanomechanical response of cantilevers to biomolecular binding.
• To assess the sensitivity, specificity, and thermodynamic analysis capabilities of the cantilever array.

Main Methods:

• Fabrication of microcantilever arrays on silicon.
• Optical detection of nanomechanical bending induced by ligand-receptor binding (DNA hybridization, protein recognition).
• Differential measurements using reference cantilevers for enhanced specificity.

Main Results:

• Simultaneous detection of multiple unlabeled biomolecules at nanomolar concentrations within minutes.
• Sequence-specific DNA detection with discrimination of overhangs and high background tolerance (80-fold excess nonmatching DNA).
• Nanomechanical motion attributed to steric hindrance, dependent on DNA concentration; femtomole detection achieved.

Conclusions:

• Cantilever arrays provide a sensitive and specific platform for label-free, multiplexed biomolecular detection.
• The system allows for in situ investigation of biomolecular interaction thermodynamics.
• This technology enables parallel binding assays with high sensitivity and specificity.